Assessing Fear Following Retrieval + Extinction Through Suppression of Baseline Reward Seeking vs. Freezing.
Assessing Fear Following Retrieval + Extinction Through Suppression of Baseline Reward Seeking vs. Freezing.
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DOI：
10.3389/fnbeh.2015.00355
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发表时间：
2015
影响因子：
3
通讯作者：
Monfils MH
中科院分区：
文献类型：
--
作者：
Shumake J;Monfils MH
冻结已成为啮齿类动物条件恐惧研究中使用的主要测量方法，但对奖励寻求行为的条件抑制可能提供一种与人类焦虑症更相关的测量方法；也就是说，这是一种衡量恐惧如何干扰享受愉快活动的方法。先前的研究发现，在消退训练（恢复+消退）之前，孤立地呈现恐惧条件刺激（CS）会导致更强大、更持久的恐惧减少。本研究的目的是通过对奖励寻求的条件抑制来评估检索+消失效应是否明显，通过减少基线舔食（没有事先缺水）来操作10%蔗糖溶液。我们发现，与冻结相比，寻求奖励的条件抑制对恐惧条件反射要敏感得多，对消失训练的反应要小得多。与之前的研究一样，我们发现，当被测量为冻结时，检索+消失减少了灭绝后恐惧的恢复，但当被测量为条件抑制时，它没有减少恐惧的恢复。这表明，在检索+消失之后仍然存在残余的恐惧，或者这一过程只改变了与冻结表达相关的神经回路中的记忆痕迹，而不是抑制奖励寻求。
Freezing has become the predominant measure used in rodent studies of conditioned fear, but conditioned suppression of reward-seeking behavior may provide a measure that is more relevant to human anxiety disorders; that is, a measure of how fear interferes with the enjoyment of pleasurable activities. Previous work has found that an isolated presentation of a fear conditioned stimulus (CS) prior to extinction training (retrieval + extinction) results in a more robust and longer-lasting reduction in fear. The objective of this study was to assess whether the retrieval + extinction effect is evident using conditioned suppression of reward seeking, operationalized as a reduction in baseline licking (without prior water deprivation) for a 10% sucrose solution. We found that, compared to freezing, conditioned suppression of reward seeking was much more sensitive to fear conditioning and far less responsive to extinction training. As in previous work, we found that retrieval + extinction reduced post-extinction fear reinstatement when measured as freezing, but it did not reduce fear reinstatement when measured as conditioned suppression. This suggests that there is still residual fear following retrieval + extinction, or that this procedure only modifies memory traces in neural circuits relevant to the expression of freezing, but not to the suppression of reward seeking.